Estudos epidemiológicos da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades indígenas do município de Pauini, Amazonas, Brasil

The Mansonella ozzardi has a widespread distribution among the indigenous and riverine communities of Amazonas, Brazil. We estimated the prevalence of Mansonella ozzardi in indigenous communities of the Pauini municipality, Amazonas state, Brazil and the rate of parasitic infection in vectors. We collected thick blood smears from individuals from six Apurinã indigenous communities along the Purus River and its tributaries. Collections of simuliids were made and dissected, and the larval instars of M. ozzardi identified. The overall prevalence of M. ozzardi was 28.40%, with the highest incidence among males and agricultural workers. Among age groups, children 2-9 years of age had the lowest incidence, while individuals older than 58 exhibited the highest rates of infection. We found infected simuliids in three communities, with Parasitic Infection Rates (PIR) of 0.34-6.58%. The prevalence of M. ozzardi among the Apurinã people is high, possibly related to the diary activities of the riparian people, where a high abundance of the vectors exists.Esse trabalho tem como objetivos estimar a prevalência de Mansonella ozzardi em comunidades indígenas do município de Pauini, Amazonas, Brasil e estimar a Taxa de Infecção Parasitária nos vetores. Foram examinados indígenas da etnia Apurinã, pelo método de gota espessa, em seis comunidades localizadas as margens e afluentes do rio Purus. A prevalência geral para M. ozzardi foi de 28,40%, com maior incidência para o sexo masculino e nos indivíduos com atividade no campo (agricultores). Em relação à faixa etária, as menores prevalências foram obtidas nos indivíduos mais jovens (2-9 anos), enquanto as maiores nos indivíduos acima de 58 anos. Foram encontrados simulídeos parasitados em três comunidades, com uma Taxa de Infecção Parasitária que variou de 0,34 a 6,58%. A prevalência de M. ozzardi entre os Apurinã é elevada, possivelmente relacionada às suas atividades diárias as margens dos rios, onde existe uma grande abundância dos vetores

Description of two new species of Palpomyia Meigen (Diptera: Ceratopogonidae) from the Brazilian Amazon

Resumo. Duas novas espécies de insetos predadores e bioindicadores da qualidade da água do gênero Palpomyia, grupo distincta, são descritas e ilustradas baseadas em espécimes machos. Os imaturos das espécies Palpomyia amazonensis sp. nov. e Palpomyia lanceolata sp. nov. foram coletados em armadilhas ovitrampas e criados em laboratório até adultos. Ambas novas espécies são semelhantes a Palpomyia guyana Clastrier, 1992 e Palpomyia turnbowi Grogan et al., 2013 e diferem de Palpomyia versicolor Macfie, 1939, única espécie do grupo distincta descrita na Amazônia Brasileira. Com as duas descrições, foram aumentadas para três o número de espécies para a Amazônia e 32 para o Brasil. Descrição de duas novas espécies de Palpomyia Meigen (Diptera: Ceratopogonidae) da Amazônia brasileira Abstract. Two new Amazonian predaceous midge of the genus Palpomyia, from the distincta group, were described based on male specimens. This genus is an important bioindicator of aquatic environments. The immatures of Palpomyia amazonensis sp. nov. and Palpomyia lanceolata sp. nov. were collected with ovitraps and reared in laboratory until adulthood. Both new species are similar with Palpomyia guyana Clastrier, 1992 and Palpomyia turnbowi Grogan et al., 2013 but differs from Palpomyia versicolor Macfie, 1939, the unique species described in Brazilian Amazon until now. With the description of these new species we increase to three the representative species of the distincta group in the Brazilian Amazon and to 32 the number of Brazilian species of Palpomyia

Hematophagous biting midges (Diptera: Ceratopogonidae) from Tefé municipality, Amazonas state, Brazil

Some species of biting midges are vectors of pathogens that cause disease in vertebrates, including humans. The aim of this study was to survey the biting midge fauna in Tefé, Amazonas, Brazil. Culicoides were collected using HP light traps during January, February, and April 2013. Midges collected included one species from the genus Lectoconops that bites humans. A total of 248 Culicoides individuals were collected, representing 19 species from two subgenera (Haematomyidium and Hoffmania) and four informal species groups (carpenteri, leoni, fluvialis, and reticulatus). Twelve individuals of L. brasiliensis were also collected, and this is the first record of L. brasiliensis in Amazonas. Three species of Culicoides were also recorded for the first time in Amazonas, including Culicoides aitkeni, C. glabellus and C. ocumarensis. The most abundant species were C. hylas (81 individuals), and C. foxi (27). The Culicoides fauna in Tefé is diverse, and proven vectors such as C. paraensis and C. insignis were found

Diversity of biting midges Culicoides (Diptera: Ceratopogonidae), potential vectors of disease, in different environments in an Amazonian rural settlement, Brazil

The Culicoides transmit a variety of pathogens. Our aim was to survey the Culicoides species occurring in an Amazonian rural settlement, comparing abundance, richness, and diversity in different environments. METHODS: Culicoides were captured using CDC light traps. The Shannon-Wiener (H') and Rényi indices were used to compare species diversity and evenness between environments, the equitability (J') index was used to calculate the uniformity of distribution among species, and similarity was estimated using the Jaccard similarity index. A permutational multivariate analysis of variance was applied to assess the influence of environment on species composition. A non-metric dimensional scale was used to represent the diversity profiles of each environment in a multidimensional space. RESULTS: 6.078 Culicoides were captured, representing 84 species (45 valid species/39 morphotypes). H' values showed the following gradient: forest > capoeira > peridomicile > forest edge. The equitability J' was greater in capoeira and forests compared to peridomiciles and the forest edge. The population compositions of each environment differed statistically, but rarefaction estimates indicate that environments of the same type possessed similar levels of richness. Species of medical and veterinary importance were found primarily in peridomiciles: C. paraensis, vector of Oropouche virus; C. insignis and C. pusillus, vectors of Bluetongue virus; C. filariferus, C. flavivenula, C. foxi, and C. ignacioi, found carrying Leishmania DNA. CONCLUSIONS: This study indicates that diversity was higher in natural environments than in anthropized environments, while abundance and richness were highest in the most anthropized environment. These findings suggest that strictly wild Culicoides can adapt to anthropized environments

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Local hydrological conditions influence tree diversity and composition across the Amazon basin

Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R$^{2}$ = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R$^{2}$ = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions